1. Field of the Invention
The present invention relates generally to an adjustable apparatus for use in cleaning and polishing rolls used in the rolling of sheet stock such as, for example, sheet steel, sheet plastic, paper, and the like.
2. Description of the Prior Art
During the manufacture and processing of sheet stock, such as, for example, sheet steel, sheet plastic, paper, and the like, it is oftentimes advantageous to wind the sheet stock on rolls or into coils for ease of handling, storage, and transportation. In preparing such large rolls of stock, it is also often necessary to translate the sheet stock through a series of motor and friction driven rolls prior to the final stage of forming the large rolls or coils. During the translation of the sheet stock across the motor and friction driven rolls, particles of metal, plastic, paper, and the like, may become dislodged from the stock and may build up on or become embedded in or otherwise damage the surface of the motor and friction rolls, particularly those rolls having a polished metallic surface. For example, in steel industry rolling mills, it has long been recognized that small metallic pieces, or chips, of the sheet steel stock being processed are dislodged from the strips of stock and build up on the surface of the motor and/or friction driven rolls used in the mills. These chips often build up on the surface of the rolls, with the result of not only damaging the surface of the rolls themselves but also damaging the stock being processed, such as by scratching or marking the stock. Obviously, metal, plastic, or other material so damaged cannot be used in producing a final consumer product because of surface imperfections caused by such scratching. Indeed, in certain steel industry rolling mill operations, surface scratching caused by small metallic chips may account for approximately 5-10% wastage of the processed sheet metal.
In the current rolling mill and other similar operations, various types of methods have been tried to clean the rolls. However, these methods have met with only limited success. For example, one such method involves attaching a piece of abrasive material, such as emery cloth, to the end of a 2".times.4" board and, while an operator holds the opposite end of the board, putting the end of the board on which the emery cloth is fastened against the face of the roll as the roll is turned at high revolutions per minute. This method not only produces an unsatisfactory cleaning operation but also is extremely dangerous to the operator.
Further, other current cleaning methods involve shutting the line down, cutting the sheet stock and attempting to clean the rolls with hand-held power grinders.
In many instances, the surface of the polished rolls cannot be cleaned by these, and other, current practices and the rolling mill line must be shut down until the damaged rolls can be replaced. This contributes to additional operational expenses. For example, it is known that in certain steel industry rolling mill operations, downtime of the rolling mill apparatus may represent a cost approaching approximately $500.00 per minute of downtime.
Some mills have roll polishing machines that pneumatically force an abrasive stone block against the face of the roll. The stone block, with the associated pneumatic device, such as an air cylinder, is translated across the length of the surface of the roll at very slow rates of speed. When using such machines, by the time the stone block traverses the length of the roll, material builds up on the roll causing damage to the sheet stock. These machines, which are oftentimes driven by electric motors equipped with gear reduction devices, are expensive and require significant maintenance. In addition, due to the high contact pressure applied to the stone block and hence the roll, the surface finish of the roll is often damaged. This results in an added expense of refinishing the roll, at a cost approaching $5,000 to $7,500 per roll.
Other prior art devices used to clean and polish rolls have used a polishing block or stone, made from silicon carbide, felt, or the like, that is manually forced against the surface of the roll. One such prior art device was manufactured and sold by the assignee of the present application. That device had a series of polishing blocks attached to block holder arms. The holder arms were, in turn, attached, through a first rotational joint, to extensions of a first shaft. The first shaft was attached, at each end thereof, to shaft holders having arms extending therefrom. These arms were provided with second rotational joints through which passed a second shaft. The second shaft had a manually operated lever. In addition, the second rotational joints were connected to paired housings which were, in turn, attached to base plates. The base plates were adapted for attachment to support structures located on each side of the roll to be cleaned.
In use, the housings of this prior art device could be positioned along threaded shafts to control the height of the polishing blocks above the roll. When it was desired to cause the polishing blocks to contact the surface of the roll, the lever was manually depressed. The second rotational joints then allowed the arms, and hence the shaft holders, to move in an arcuate fashion toward the surface of the roll. The first rotational joint caused the polishing blocks to contact the surface of the roll substantially tangent to that surface. However, during operation, the polishing blocks displayed a marked tendency to scar the surface of the spinning roll due to the manual force required to maintain the blocks in contact with that surface. In addition, in that device, the blocks were held in position against the surface of the roll and did not traverse or oscillate across a portion of the roll's surface. This had the effect of causing a further scarring of the surface of the roll.
In my U.S. Pat. No. 4,528,716, issued on July 16, 1985, I disclosed a device for cleaning roll assemblies. That device utilizes a knife-edge blade arrangement to clean the surface of roll assemblies. However, that device did not provide a mechanism for polishing the rolls, nor did it provide a means for oscillating the blade arrangement across the surface of the roll.
On the other hand, the novel apparatus of the present invention overcomes the foregoing deficiencies noted in the prior art by providing an apparatus which cleans the surfaces of spinning rolls, generally across the entire length of the roll, removes therefrom the small chips which may damage the rolls and the sheet stock, and polishes the surface of the rolls to a relatively smooth surface. Accordingly, it is an object of the present invention to provide an apparatus for cleaning and polishing rolls which does not have the inherent deficiencies of the prior art.
It is another object of the present invention to provide a cleaning and polishing apparatus which includes at least one abrasive stone, and preferably more than one abrasive stone, positionable to contact the surface of the roll, thereby allowing the small chips to be removed from the roll prior to building up on the surface of the roll or otherwise damaging the surface of the sheet stock and permitting the roll to be polished.
It is yet a further object of the present invention to provide a cleaning and polishing apparatus which is adjustable through numerous axes so as to permit ready placement of the stone against the roll being cleaned.
These and other objects and advantages of the present invention will become apparent to those skilled in the art with reference to the foregoing, the attached drawings, and the description of the invention which hereinafter follows.